Apparatus for applying catheter



April 24, 1962 3,030,953

W. R. KOEHN APPARATUS FOR APPLYING CATHETER Filed 001;. 17, 1957 2Sheets-Sheet 1 vw Z7///////////////////// A Aprll 24, 1962 w. R. KOEHN,9

APPARATUS FOR APPLYING CATHETER Filed Oct. 17, 1957 2 Sheets-Sheet 2INVENTOR.

W/zaufi fiZEH/V B arra /1434s nitedStates 3,030,953 Patented Apr. 24,1962 3,030,953 APPARATUS FOR APPLYING CATHETER Wilbur R. Koehn, NewYork, NY. Shorewood Drive, Sands Point, Long Island, N.Y.) Filed Oct.17, 1957, Ser. No. 6%),709 9 Claims. (Cl. 128-2l4) The present inventionrelates to a method of and surgical apparatus for applying a cathetertube to any re quired location in the human body.

It is a usual practice in blood transfusions, intraveneous feeding orwhen fluids are to be withdrawn from the body to attach a tube to ahollow needle and insert the needle into a vein or other body cavity.The fluid then flows through the tube and hollow needle into the bodywhen fluids are to be delivered therethrough or through the needle andtube when fluids are to be withdrawn.

Repeated punctures of veins with metal needles for withdrawingsuccessive blood samples, elivering successive transfusions orintravenous feeding, tend to cause venous thromboses and subcutaneoushematomas. It has, therefore, become a common practice to leave theneedle in the body for long periods of time. To prevent relativemovement of the body and needle, the part of the body where the needleis inserted must be immobilized with considerable discomfort to thepatient. This is especially true when the needle is inserted into avein, as, for example, in the arm, where relative movement might cause apuncturing of the vein and additional trauma. To prevent such relativemovement the arm is strapped in fixed position.

Obviously, it would be desirable to insert the end of a soft flexiblecatheter into a body cavity instead of a needle. It has heretofore beenproposed to so insert the end of a catheter tube into a vein or otherbody cavity by means of a needle and then withdraw the needle. One suchmethod requires the use of a relatively large hollow needle to make theincision, telescoping the end of the tube through the hollow needle andthen withdrawing the needle over the catheter tube. Such a method ofinserting a catheter tube produces a large incision and excessivecutting of the tissue and is especially undesirable when the incision ismade in a vein.

It has also been proposed to attach the end of a catheter tube to aneedle and then withdraw the needle through the catheter. With thisproposed arrangement, openings are provided in the sides of a relativesmall hollow needle. The catheter tube surrounds the needle and hasforwardly projecting tabs which are inserted into the openings in theneedle. A stylet is then inserted through the hollow needle to clamp theends of the tabs against the interior sides of the needle. Thisarrangement is impractical because of the complicated structuresrequired, the very small dimensions of the parts and the difiiculty ofmanually inserting the ends of tabs at the end of a catheter into thevery small openings at the sides of a small needle.

One of the objects of the present invention is to provide an improvedmethod of and surgical apparatus for inserting the end of a cathetertube to any desired location in the human body.

Another object is to provide a method of and apparatus for inserting acatheter tube into the body with the aid of a relatively small needleand then withdrawing the needle through the catheter.

Still another object of the present invention is to provide a method offorming a catheter tube to provide a blunt end having a rounded outeredge.

Another object is to provide a surgical apparatus of the type indicatedwhich may be hermetically sealed in an enclosing casing for storage as aself contained sterile unit.

Another object is to provide a surgical apparatus of the type indicatedin which the flow of blood can be observed to show when the end of thecatheter has entered a vein.

Still another object is to provide a surgical apparatus of the typeindicated which is of simple and compact construction adapted foreconomical manufacture and one which is reliable in operation.

These and other objects will become more apparent from the followingdescription and drawings in which like reference characters denote likeparts throughout the several views. It is to be expressly understood,however, that the drawings are for the purpose of illustration only andare not a definition of the limits of the invention, reference being hadfor this purpose to the appended claims.

In the drawings:

FIGURE 1 is a greatly enlarged longitudinal sectional View of apreferred form of surgical apparatus incorporating the novel features ofthe present invention;

FIGURE 2 is an enlarged view of one end of the needle and catheter tubeand showing the blunt end of the tube with its outer edge slightlyrounded;

FIGURE 3 is a view similar to FIGURE 2 showing the manner in which thecatheter tube yields radially to permit the enlarged head of the needleto be withdrawn therethrough;

FIGURE 4 is a longitudinal sectional view of the as semb'led needle andcatheter tube illustrated in FIGURES l to 3 with a finger grip at theend of the needle shaft in the form of a stopple for hermeticallysealing the needle and catheter assembly in an enclosing casing;

FIGURE 5 is an enlarged sectional view of a needle o-f modifiedconstruction for indicating the flow of blood.

FIGURE 6 is a sectional plan view of the needle illustrated in FIGURE 5to show the bore in the pointed head and groove in the shank;

FIGURE 7 is a sectional view similar to FIGURE 5 showing a needle with adifferent form of point for in"- sertion in a body cavity;

FIGURE 8 is a sectional plan view of the needle illustrated in FIGURE 7;

FIGURE 9 is a sectional view similar to FIGURE 2 showing a needle andcatheter tube of modified construction for clamping the end of the tubeto the needle;

FIGURE 10 is a view similar to FIGURE 2 showing a needle and catheter ofanother modified construction;

FIGURE 11 is a sectional view of aneedle of another modifiedconstruction having spring fingers adapted to be flexed outwardly toprovide a continuous surface from the head of the needle to the outsidediameter of the catheter tube; and

FIGURE 12 is a view similar to FIGURE 11 showing the spring fingersreleased and retracted to the inside diameter of the catheter tube; and

FIGURE 13 is a longitudinal sectional view of a rod inserted in thecatheter tube to plug the tube when required.

The method of the present invention is based on the discovery that aconventional catheter tube with an annular end cut at right angles toits axis will follow a puncturing needle to the desired location in thebody without deformation of the end of the tube or tearing the fibers ofthe skin and tissue as it passes therethrough. More surprisingly, it hasbeen discovered that a needle having a puncturing head of a largeroutside diameter than the inside diameter of the catheter tube may bewithdrawn through the tube without displacing its end.

Therefore, in accordance with the method of the present invention, acatheter tube com-posed of a suitable chemically inert resilientmaterial is formed with an end terminating in a plane at right angles toits axis. The

' blunt end on such a catheter of a suitable material renders itsufficiently rigid to prevent deformation when inserted into bodytissue, but sufficiently resilient to expand radially to permit theneedle head of larger diameter than the inside diameter of the tube tobe withdrawn therethrough. Such materials include those used inconventional catheter tubes such as polyethylene, polyvinyl and nylonplastics. For example, a catheter tube of polyethylene having an insidediameter of .047 inch and an outside diameter of .065 inch has been usedwith a needle corresponding substantially to a conventional No. 19needle and having a head with an outside diameter of .057 inch.

The blunt end of the catheter tube projects radially from its insidediameter in a right angular shoulder through at least one-half the wallthickness. Preferably, the right angular shoulder extends radiallyoutwardly for two-thirds of the wall thickness with its outer peripheraledge slightly rounded. The blunt end of the catheter tube may be formedby molding it in asuitable mold. However, one particular method offorming a blunt end which has been successfully used is to slide asection of a conventional plastic catheter tube over a rod havingsubstantially the same inside diameter and then rolling the tube on aflat surface under a blade which flares at a wide angle from the cuttingedge. When so cut, the blunt end of the tube has an annular shoulder ina plane at right angles to its axis which extends radially outwardlyfrom its inner diameter for about two-thirds of its wall thickness witha gradual rounding of the remaining onethird of the wall thickness tothe outer periphery of the tube. Therefore, the term blunt as used inthe specification and claims is intended to mean that the terminal endlies in a plane at right angles to its axis, but includes a slightrounding at the outer peripheral edge of the shoulder or even a taperfrom the blunt end to the outer periphery of the tube.

The catheter tube is made only long enough to adapt its blunt end to beinserted into the body cavity and project outwardly from the body. Thus,the catheter tube is only several inches in length and is adapted to beconnected to a tube extension after the blunt end has been inserted intothe body. For this purpose, the end of the catheter tube opposite theblunt end is formed with a conventional tapered fitting for connectionwith a tube extension. The tapered fitting also may be molded as anintegral part of the catheter tube or may be molded as a separate pieceand thereafter attached to the end of the tube as by welding it theretoby the application of heat.

The formed catheter tube is applied to a needle having a head with apointed end and a reduced shank projecting rearwardly from the head andforming an annular shoulder therebetween. The reduced shank of theneedle is only slightly smaller than the inside diameter of the tube toprovide a limited clearance of capillary dimensions. The needle may beformed in a conventional manner by grinding the head on a bias to itsaxis to form a sharp pointed end for puncturing the skin and tissuewhich progressively widens to the outside diameter of the head. Theblunt end of the catheter tube when applied to the shank of the needleabuts the annular shoulder between the head and shank. In accordancewith the present invention the head of the needle has a greater outsidediameter than the inside diameter of the catheter tube to provide aguide for the end of the tube. The annular shoulder on the needleoverlies at least a portion of the blunt end of the catheter tubeadjacent its inner periphery. Preferably, the annular shoulder on theneedle extends radially to about one-half the thickness of the tubewall, but may extend to the outside diameter of the tube. The rightangular shoulder on the blunt end of the catheter tube then abuts theannular shoulder on the needle and may project beyond the needle headwith the outwardly projecting portion rounded or rearwardly tapered tothe outside diameter of the tube.

It is desirable to have the needle head of as small dimensions aspossible to reduce the size of the incision made by the needle head to aminimum. However, if the annular shoulder on the needle is made tooshallow, the end of the catheter tube tends to catch on the tissuefibers and does not readily follow the needle point. If the annularshoulder on the needle is made too high it increases the size of theincision and requires a greater expansion of the tube to accomodate thehead when the needle is withdrawn. Thus, the head of the needle has alarger diameter than the inside diameter of the catheter tube and theblunt end of the catheter tube preferably projects radially beyond thehead of the needle approximately onehalf of its wall thickness with theoutwardly projecting edge of the tube slightly rounded. It is to beunderstood, however, that variations may be made in the relationship ofthe needle head and catheter tube. For example, if a thin wall cathetertube is used or if the material is especially flexible, the annularshoulder on the needle may overlie a greater area of the end of thetube. It has been determined by experiment that a catheter tube ofpolyethylene having an outside diameter of .061 inch, an inside diameterof .045 inch and used with a needle having a shank of .041 inch and ahead of .061 inch operates satisfactorily to insert the catheter andremove the needle.

The blunt end of the catheter tube is inserted into a body cavity suchas a vein by inserting the pointed sharpened end of the needle into thebody at the desired location. The pointed end of the needle cuts a holein the slain and tissue through which the blunt end of the catheter tubewill follow the needle to the desired location in the body even when itprojects radially beyond the head of the needle and will pass betweenthe elastic fibers of the tissue and spread them apart without catchingor tearing the fibers. During such movement the tension of the tissuefibers tends to move the end of the catheter away from the shoulder andinwardly toward the shank of the needle and provide a capillary paththrough which blood will flow and be observed through the transparenttube wall when the needle head enters a vein. However, the blunt end ofthe tube is sufficiently rigid to prevent any substantial deformation.

When the blunt end of the catheter tube has been inserted to the desiredlocation in the body the tube is held with one hand and the rearwardlyprojecting end of the needle shank is grasped between the fingers of theother hand and withdrawn relative to the catheter tube. Surprisingly,the blunt end of the catheter tube expands radially to permit theshouldered head of the needle to pass therethrough as the needle isWithdrawn. The blunt end of the catheter tube does not fold back onitself or catch on one side of the needle or split, but instead ityields uniformly around its entire periphery to permit the enlarged headto pass therethrough. After the needle has been withdrawn from the tube,the catheter tube is taped on the body to hold it in a fixed positionand a tube extension is applied to the fitting at its exterior end. Acatheter tube so applied may be left in the body for a long period oftime without any detrimental affect. Furthermore, the area where thecatheter tube is applied does not need to be immobilized as therelatively flexible tube yields to accommodate itself to any movement ofthe body. When it is desired to close the tube to stop the flow of bloodtherethrough, a rod of plastic material of substantially the same lengthand outside diameter as the length and inside diameter of the tube isinserted to plug the tube.

Several embodiments of surgical apparatus used in accordance with theabove described method and incorporating the present invention areillustrated in the drawings. As shown in FIGURES l and 2, the surgicalapparatus comprises a needle 1 having a head 2 and a reduced shank 3projecting rearwardly therefrom and forming an annular shoulder 4therebetween. The forward end of the head 2 is hollow ground to providea pointed end 5 for puncturing skin and underlying tissue. Surroundingthe shank 3 is a catheter tube 6 having a blunt end 7 abutting theannular shoulder 4 on the needle and a tapered fitting 8 at its oppositeend. The reduced shank 3 is of a length to project rearwardly from thecatheter tube 6 beyond the fitting 8.

In the illustrated embodiment, the blunt end 7 of the catheter tube 6projects radially beyond the annular shoulder 4 of the needle head 2 andhas a slightly rounded edge 9 at its outer periphery. Preferably, theblunt end 7 of the catheter tube 6 projects radially beyond the annularshoulder 4 of the needle 1 a distance substantially equal to the heightof the annular shoulder and the rounded peripheral edge 9 extendsthrough approximately one-third of the wall thickness of the cathetertube 6.

A hand grip 10 is provided on the rearward end of the shank 3 of theneedle 1 which projects beyond the tapered fitting 8 of the cathetertube 6 to adapt the needle to be withdrawn through the tube. Forpurposes of illustration, the hand grip 10 is illustrated in the form ofa detachable handle having a central bore for receiving the end of theshank and attached thereto by a set screw 11. It will be understood,however, that the handle 10 may take other forms and may be attachedthereto as an integral part of the shank.

The needle 1 and catheter tube 6 are composed of chemically inertmaterials. For example, the needle may be made of stainless steel andthe catheter tube may be made of polyethylene plastic. The needle head 2and catheter tube 6 may be made in different sizes and the constructionof the present invention permits a needle and tube of relatively smallsize to be used. For example, the catheter tube may be made ofpolyethylene with an inside diameter of .047 inch and an outsidediameter of .065 inch and the head 2 of the needle may have an outsidediameter of .057 inch and the shank an outside diameter of .043 inch.

The blunt end 7 of the catheter tube 6 is inserted to the desiredlocation in the body by holding the assembled tube and needle betweenthe forefinger and the thumb and pressing the pointed end 5 of theneedle into the skin and tissue. As explained above, the pointed end ofthe needle cuts a small hole in the skin and tissue and the end 7 of thecatheter tube 6 follows the head 2 of the needle through the skin andtissue to the desired location. When the end 7 of the tube is properlylocated in the body, the tube is held by one hand and the needlewithdrawn relative thereto by means of the hand grip 10. During suchretraction of the needle 1, the head 2 moves relative to the cathetertube 6 from the position illustrated in FIG- URE 2 to that illustratedin FIGURE 3 and the blunt end 7 of the catheter tube 6 yields radiallyto permit the enlarged head 2 to pass therethrough in the mannerillustrated in FIGURE 3.

FIGURE 4 illustrates a construction for adapting an assembled needle .1and catheter tube 6 as shown in FIG- URE l to be sterilized andhermetically sealed in an enclosing casing. The needle 1 and thecatheter tube 6 as illustrated in FIGURE 4 are identical with thoseillus trated in FIGURE 1 except that the hand grip at the rearward endof the needle shank 3 is in the form of a stopple 15. The stopple may becomposed of a suitable plastic such as polyethylene and is molded orotherwise attached to the end of the shank of the needle as an integralpart thereof. The stopple 15 has oppositely directed conical tapers 16and 17 to adapt it to be pressed into and tightly fit the open end 18 ofa cylindrical casing 19 of plastic or the like.

With the construction illustrated in FIGURE 4, the assembled needle 1and catheter tube 6 as well as casing 19 may be thoroughly cleaned andsterilized after which the tapered end 16 of the stopple 15 is pressedinto the open end 18 of the casing 19 to engage the sides of the casingand form a hermetic seal. The assembled sterile unit may then be storedfor future use. When it is desired to use the catheter tube 6 thestopple 15 and attached needle 1 and catheter 6 assembly are removedfrom the casing 19 and reversed and the tapered end 17 pressed into theend of the casing. The casing 19 then operates as a handle from whichthe needle 1 and catheter 6 assembly project. The forward end of theneedle 1 is then inserted in the manner previously described and theneedle withdrawn by means of the casing 19 operating as a hand grip.

FIGURES 5 and 6 illustrate a modified needle construction for visuallyindicating when the end of the needle and catheter tube have entered avein. The needle 1a as illustrated in FIGURES 5 and 6 has a head 2a andshank 3a with an annular shoulder 4a therebetween like the needleillustrated in FIGURE 1. However, the head of the needle 2a has a bore20 extending from the forward face of the needle to the periphery ofshank 3a at the rear of the shoulder 4a. A longitudinal groove 21extends along the periphery of the needle shank 3a from the rearward endof the bore 20 to the rearward end of the shank. A catheter tube 6asurrounds the shank 3a of the needle and has a blunt end 7a abutting theshoulder 4a on the needle. As the polyethylene catheter tube 6a istransparent, blood can be observed as it flows along the groove 21.Thus, the needle 1a and catheter 6a assembly illustrated in FIGURES 5and 6, will indi cate when the end of the needle 5 has penetrated avein.

FIGURES 7 and 8 illustrate another modified construction of needle head.In this construction the needle it: has a head 2b and a shank 3b with anannular shoul der 4b as previously described. The pointed end 5b,however, is in the form of a narrow head for cutting a larger openingfor leading the blunt end 7b of the catheter tube 6b to a desiredlocation in the body. This type of needle 1b is particularly applicablefor the insertion'of the catheter tube into deep cavities such as thechest or abdomen.

FIGURE 9 illustrates another modified construction of needle andcatheter tube assembly in which the forward end of the catheter tube isgripped to the needle head. In the construction illustrated in FIGURE 9a needle 10 has a head 20 and a reduced shank 3c projecting rearwardlyfrom the head to form an annular shoulder 40 therebetween. However, inthe modified construction illustrated in FIGURE 9 the shank 3c is ofconsiderably reduced diameter and the annular shoulder 40 is in the formof a rearwardly directed cone. Also, the forward end 25 of the cathetertube 60 is inclined inwardly to overlie the rearwardly directed conicalshoulder 40 on the needle head. The inwardly directed end 25 of thecatheter tube 60 may be initially molded or may be produced by merelyheating and forming the blunt end of the plastic tube to the desiredshape. A sleeve 26 is mounted to slide on the shank 3c of the needlewhich has a conical front face 27 for engaging the inwardly directed end25 of the tube to clamp it against the conical shoulder 40 of the needle10. Thus, the portion of the forward end 25 of the catheter tube 60which projects radially from the needle head 20 constitutes an annularblunt end which follows the needle head through the skin and tissue.

The forward end of the needle 10 and catheter 60 assembly are insertedin the same manner as previously explained. When the end 25 of thecatheter tube 60 is properly located, the sleeve 26 is slid rearwardlyto release the end 25 after which the catheter tube is slid rearwardlyrelative to the sleeve. The end 25 yields as it slides over the sleeve26 to stretch it to the outer periphery of the sleeve. Sleeve 26 is thenpressed forwardly into engagement with the annular shoulder 4c on thehead of the needle 20 to form a continuous surface and the needle 10 iswithdrawn through the tube. With this construction the head 2c andsleeve 26 of the needle 10 provide a continuous surface of the samediameter as the inside diameter of the tube 60 to facilitate the removalof the needle.

FIGURE illustrates another modified construction in which the head andshank of the needle have the same outside diameter with an intermediaterecessed portion therebetween. The needle id illustrated in FIGURE 10has a head 2d similar to that illustrated in FIGURE 1 with an annularshoulder 4d at the rear of the head. The shank 3d then tapers outwardlyfrom the shoulder 4d to a diameter equal to the outside diameter of thehead 2d at a normal plane 30 rearwardly of the shoulder. The shank 3dthen extends rearwardly from plane 30 at the same diameter. The forwardend portion 31 of the catheter tube 6d tapers inwardly from the plane 39to the shoulder 44'. Forward blunt end 7d of the catheter tube 6d abutsthe shoulder 4d, but in this construction the blunt end does notnecessarily project radially beyond the head 2d of the needle and theinclined forward portion 31 forms a continuous surface from the outerperiphery of the head to the outer periphery of the tube. Theconstruction illustrated in FiGURE 1O facilitates the insertion of theend of a catheter tube 6d of a particular size with a smaller needle.

FIGURES 11 and 12 illustrate a still further modified construction ofneedle adapted to be expanded to form a continuous surface from the headof the needle to the outside diameter of the catheter tube duringinsertion and to be contracted to the inside diameter when withdrawn.The needle 1e illustrated in FIGURES 11 and 12 has a head 2e and shank3e to form an annular shoulder 42 therebetween. Projecting rearwardlyfrom the hea i is of the needle are a series of spring fingers 35. Thespring fingers 35 may be formed by counter boring the needle 1e betweenthe shank 3e and the periphery of the head 2e and then slotting the cuffso formed to form the series of fingers. Mounted to slide on the shank3c is a sleeve 36 having a tapered forward end forming an annular camface 37. Thus, by sliding the sleeve 36 forwardly as shown in FIGURE 11the cam face 37 at the end of the sleeve 36 expands the spring fingersto provide a continuous surface from the outside diameter of the head 22to the outer periphery of the catheter tube 62. By sliding the sleeve 36rearwardly relative to the catheter tube 62 the spring fingers 35 arereleased which flex back to their normal position illustrated in FIGURE12 to substantially the same diameter as the inside diameter of thecatheter tube 6a. This construction facilitates the insertion of the endof the catheter as well as the removal of the needle after the cathetertube has been properly located in the body.

FIGURE 13 illustrates a rod 40 used to plug the catheter tube 6 whenrequired. The rod 40 is made of a pla tic material such as polyethyleneand has a handle 41 at its rearward. Handle 41 has a portion of the samecontour as the fitting 8 at the rearward end catheter tube 6. Rod 4% hassubstantially the same diameter as the inside diameter of the cathetertube 6 and extends forwardly from the handle a distance equal to thelength of the tube with a smooth rounded end 42 adapted to projectslightly beyond the end of the tube when the handle 41 is seated in thefitting 8. When it is desired to stop the flow of blood, the rod 40 ismerely inserted through the rearward end of the catheter tube until thehandle 41 is seated in the fitting 8.

It will now be observed that the present invention provides an improvedmethod of and surgical apparatus for inserting the end of a cathetertube to any desired location in the human body. It will also be observedthat the present invention provides a method of and surgical apparatusfor inserting a catheter tube to a desired location in the body by meansof a puncturing needle and then withdrawing the needle through the tube.it will further be observed that the present invention provides asurgical apparatus which is of simple and compact construction, reliablein operation and one which may be made cheaply enough to render itdisposable after a single use.

While a number of embodiments of the invention are herein illustratedand described, it will be understood that further modifications may bemade in the construction and arrangements of elements without departingfrom the spirit or scope of the invention. Therefore, without limitationin this respect the invention is defined by the following claims.

I claim:

1. Surgical apparatus for delivering fluids to or withdrawing fluidsfrom the human body comprising a needle having a head with a sharp,pointed end for penetrating tissue and a shaft of uniform diameterprojecting rearwardly therefrom, an annular shoulder on the needlebetween the head and shaft, a catheter tube surrounding and contactingthe shaft of the needle through a major portion of its length and havingan end terminating in a plane at substantially right angles to its axisat the rear of the needle head, said annular shoulder on the needleoverlying at least a portion of the end of the catheter tube around itsentire inner periphery and said catheter being rigid longitudinally whenin position on the needle to prevent collapse when inserted throughtissue, and one of the parts comprising said end of the catheter tubeand shoulder on the needle being relatively flexible with respect to theother part to permit the head of the needle to be withdrawn through thecatheter tube.

2. Surgical apparatus for delivering fluids to or withdrawing fluidsfrom the human body comprising a needle having a head with a pointed endand a shaft of uniform diameter projecting rearwardly therefrom toprovide an annular shoulder therebetween, a flexible plastic cathetertube mounted on and contacting said shaft, through a major portion ofits length, the end of the catheter tube adjacent the head of the needlebeing blunt and forming an annular end at least partially covered by theannular shoulder between the head of the needle and shaft and projectingradially therebeyond, said shaft extending outwardly beyond the end ofthe tube and having a handle grip at its end to adapt the needle to bewithdrawn through the catheter tube, and said radially projecting bluntend of the tube being rigid longitudinally when in position on theneedle to follow the head of the needle through skin and tissue andflexible radially to permit the head of the needle to be withdrawntherethrough.

3. Surgical apparatus for delivering fluids to or withdrawing fiuidsfrom the human body comprising a needle having a cylindrical headpointed at one end and a shaft of uniform diameter projecting rearwardlytherefrom to provide an annular shoulder therebetween, a thin walledhollow catheter tube of polyethylene surrounding and contacting saidshaft throughout the major portion of its length and having one endterminating in a plane at substantially right angles to its axisadjacent the head of the needle and shaped at its other end to form atapered fitting, the head of the needle overlying at least a portion ofthe inner periphery of the said one end of said catheter tube and saidshaft projecting beyond the end of the fitting, and the end of the tubebeing rigid longitudinally when mounted on the needle and flexibleradially to permit the head of the needle to be withdrawn therethrough.

4. Surgical apparatus for delivering fluids to or withdrawing fluidsfrom the human body comprising a needle having a cylindrical headpointed at one end and a reduced shaft of uniform diameter projectingrearwardly therefrom to provide an annular shoulder therebetween, acatheter tube of flexible plastic material surrounding and contactingthe shaft through a major portion of its length and having an insidediameter to provide a sliding fitting with the outside diameter of theshaft and an outside diameter greater than the outside diameter of thehead, the end of the catheter tube adjacent the annular shoulder on theneedle being blunt with a sharp edge at its inner periphery and aslightly rounded edge at its outer periphery, said blunt end of thecatheter tube projecting radially beyond the head of the needle, saidshaft of the needle projecting rearwardly beyond the end of the cathetertube opposite the blunt end to adapt the needle to be withdrawn throughthe catheter tube, and said radially projecting blunt end of the tubebeing rigid longitudinally when mounted on the needle to follow the headof the needle through skin and tissue and flexible radially to permitthe larger head of the needle to be withdrawn therethrough.

5. Surgical apparatus in accordance with claim 1 in which the end of thecatheter tube opposite the end at the rear of the needle head is shapedto form a tubular fitting for detachable connection with a tubeextension.

6. Surgical apparatus in accordance with claim 1, in which the assembledneedle and catheter tube are located in a cylindrical casing having anopen end, and means on the assembly cooperating with the end of thecasing to close the casing after pasteurization to provide anhermetically sealed unit.

7. Surgical apparatus in accordance with claim 6 in which the shaft ofthe needle extends beyond the end of the catheter tube and has a handgrip at its end, and the means cooperating with the end of the casing toclose the casing is the hand grip on the rearward end on the needleshaft which cooperates with the end of the casing to provide a sealingconnection therewith.

8. Surgical apparatus in accordance with claim 1 in which the cathetertube is composed of transparent material and the needle head is hollowand the periphery of the shaft is recessed to provide a groove extendinglongitudinally thereof and connected to the hollow needle head wherebythe flow of blood through the hollow head of the needle and groove onthe shaft can be observed through the transparent catheter tube toindicate when the needle head has entered a vein.

9. Surgical apparatus for delivering fluids to or with drawing fluidsfrom the human body comprising a needle having a head With a pointed endand a shaft of uniform diameter projecting rearwardly therefrom, anannular shoulder on the needle between the head and shaft, a hollowcatheter tube of flexible material surrounding and contacting the shaftof the needle through a major portion of its length and having anannular end at right angles to its axis positioned adjacent to and atleast partially behind said annular shoulder around the entire peripheryof the shoulder and being rigid longitudinally when mounted on theneedle to cause the said tube to follow the head of the needle throughthe skin and tissue to locate the end of the catheter at the desiredposition in the body, and said shaft extending beyond the catheter tubeand having a hand grip at its end whereby to adapt the needle to bepulled rearwardly relative to the catheter tube to withdraw the headthrough the tube.

References Cited in the file of this patent UNITED STATES PATENTS396,754 Mayfield Jan. 29, 1889 1,924,785 Roig Aug. 29, 1933 2,770,236Utley et a1 Nov. 13, 1956 2,828,744 Hirsch et al. Apr. 1, 1958 2,836,180Strauss May 27, 1958

